This invention relates to tracheotomy tubes and in particular to tracheotomy tubes that incorporates an annular cannula which can be removed for cleaning without removing the exterior of the trachea tube. Tracheotomy tubes have been used to provide a bypass supply of air to the patient when an obstruction occurs within the larynx or the pharynx area, the tracheotomy tube being inserted through an incision which is placed within he patient's neck below the obstructed area.
An important requirement is that the tracheotomy tube provides a bypass air supply to the patient while minimizing the discomfort borne by the patient. Not only is it, of course, desirable to minimize the pain which the patient must suffer, but in addition it is important to minimize movement of the outer cannular once it is installed in the patient's trachea. Otherwise, the trachea are may be irritated by abrasive movement of the outer cannula. Therefore, it is important that the inner cannula be attached and detached from the outer cannula with a minimum of force exerted upon the outer cannula. Also, it is important that the air connector be allowed a degree of rotational freedom relative to the inner and outer cannulae such that normal movement of the patient relative to the air line is tolerated without exerting any torque forces upon the outer cannula.
Heretofore, there has not been available a tracheotomy tube which maintains an air tight seal between both the inner and outer cannulae and between the inner cannula and the coupling connector while at the same time allowing for easy removability of the inner cannula as well as rotational movement of the air coupling with respect to the inner cannula. For example, the prior art includes sealing arrangements positioned at various locations along the trachea tube toward the distal end and are of such a tight nature that it is necessary to apply a significant amount of force to be able to remove the inner cannula from the outer cannula. Some prior art sealing arrangements use a ridge on the inner cannula which is of a greater diameter than the interior diameter of the outer cannula. This enlarged ridge is designed to snap into a recessed ring within the interior surface of the outer cannula. These prior art sealing arrangements require that a significant amount of force be exerted upon the inner cannula in order to remove it from the outer cannula. This force results in great discomfort to the patient and irritation to the trachea area, because the outer cannula is being moved and jerked during this sealing and unsealing process.